Applications running on mobile devices are getting more and more diverse, which puts new requirements on the wireless communication networks. Currently, smart phones, laptops and tablets are the most frequently used mobile devices, but machines communicating with other machines without human intervention are expected to become the most common devices in the wireless communication networks in the future.
The current wireless communications are not properly adapted to this type of communication, which in particular for communication patterns when small amount of data is sent infrequently leads to significant performance inefficiency. This is a consequence of the rather rigid security and Quality of Service (QoS) management that the networks are supporting, but which many applications do not need. This has been observed by network operators and vendors, and efforts are ongoing to handle machine type communication in the Evolved Packet System (EPS) and Long Term Evolution (LTE).
In the longer term it is expected even larger changes to the network architecture with a closer integration of IEEE 802.11 (WLAN) based networks and cellular networks, as well as more dynamic roaming arrangements between service providers and network infrastructure providers.
However, the current solution in EPS/LTE is inefficient for single data packets because of: setup of tunnels delay for Authentication, Authorization and Accounting (AAA), User Equipment (UE) context fetch, etc. These tasks create a significant signalling and processing overhead in the network for connections that consist of very few packets. When data packets is to be sent in LTE/EPS from a UE which is initially in Radio Resource Control (RRC) idle state, a service request procedure is used, where the UE context is transferred to the eNB. LTE UE context contains UE Identities (IDs), bearer information and security information (e.g. encryption keys). This causes significant signalling and delay for small data transfers, which has been identified as a significant problem in current mobile networks as the traffic patterns get more diverse.
Therefore, 3GPP is currently working on enhancements for Machine Type Communications (MTC). The proposed solutions include allowing data to be sent over the control channels instead of the user plane to reduce the required scheduling. Another approach which comes is to keep the security context established between the UE and a core network node rather than the eNB, which was also the solution in General Packet Radio Service (GPRS). This reduces the required signalling when initiating a transmission.
The proposed solutions related to the MTC study item in 3GPP improve the current EPS network architecture by supporting connectionless services in a more efficient way. However, in a longer term, a new architecture that inherently matches the requirements of both connectionless and connection oriented services is preferable. The solution should also support dynamic roaming between different types of network and service providers in an efficient way. In addition to signalling and processing overhead there is also the problem with large delays for the initial packets when a connection is setup.
In terms of security the current solutions do provide good support for encryption in the access network. However, there are many conceivable attack vectors, and considering denial-of-service attacks it is in general dangerous to have procedures where a low amount of traffic from a host causes a large amount of work for the network.